The invention proceeds from a device on hand-held tool-driving machines for coupling pounding and/or drilling tools as well as from a tool and tool holder used with that device.
Such a device is known from EP-433 876 A1 for a tool shank. Drilling tools are designed to rotate clockwise. They are driven by the tool holder of hand-held tool-driving machines accordingly so as to rotate in a right-handed manner, i.e., in the clockwise direction. Since FIG. 5 of EP 0 433 876 A1 shows a cross section (per II--II from FIG. 1) towards the shank end, the drive direction of rotation in that case is counter-clockwise. Thus in that case the narrower of the two coupling grooves that are opposite one another is positioned in front of the locking depression in the direction of rotation. These configurations of couplings, however, bring about a non-uniform torque loading on the tool shank and on the tool holder, since first of all the axial locking feature does not transmit any significant torques and since secondly the following wider coupling has a coupling flank that is located on the side of this coupling that faces away from the axial locking feature. The three coupling flanks in that case lie within a circumferential range of less than 180.degree.0.